reinforcing trailer tongue

[phoenix02]

I need to reinforce a trailer tongue on a trailer. it is a 28ft flatbed and the tongue is 3x5x.25 angle iron. the perimeter of the main deck is 5x6.7 C Channel, I have no clue why the manufacturer made the tongue out of angle iron, but they did and so I'm here. I was planning on getting another piece of 3x5x.25 angle and welding it to the existing angle to box it, then add some gussets at the point the tongue meets the bed. The other issue is that they made the tongue very deep under the bed and the axles are set back- think more like a boat trailer than a flatbed, but this was a commercial flatbed made by a company called Ennis, about 20 years ago or so. As a result there's a lot or torsional flex that can be imparted to the bed, and I think by boxing the tongue about 3/4 of the way back under the frame, it should reinforce the tongue section and stiffen the trailer at the same time.

Sound like a plan? Am I better off getting some 3x3 thick wall tube to run inside the existing channel, or a use a 3x3 angle to box in the 3x5 so I'm welding in the web rather than at the edge of the vertical member? I've been trying to run span calculations and figure what the best option is, but I'm way out of my league in the math and trying to figure out the dynamic loading over the length of the beam while still approximating the point loading at the connection point to the bed of the trailer where dynamic down force will be strongest, so any ideas would be of great help. I'm working on moving so all my gear is already 2k miles away, I have a friend with a shop that is letting me use his Lincoln 180 Mig to stitch all this together so I can get it loaded up and on the road, so while I'm not a professional welder I am NOT a shade tree running a 90amp from HF expecting it to weld structural steel in one pass.

Trailer is a double axle 28ft 12k. I will have a 2006 Suburban 2500 on the back over the axles and a thousand or two lbs of housewares, etc, in front of that, so it will be close to capacity but still under 12k gross. Towing with a 96 F350 dually with a round bar WD hitch.

Thanks!

[SquirmyPug]

Has the tongue failed over the 20 years the trailer has been used? Flexing is a good thing, I wouldn't suggest changing anything unless there's been a problem.

[phoenix02]

that is a good point. My concern is tongue weight with the long bed in front of the axles. The PO used the trailer for transporting his tractor- he would use the front end loader to place the attachments for it on the front of the deck, then load the heavy tractor itself from the rear onto the deck over the axles. I'm just worried I'll have too much tongue weight and damage the tongue, being angle iron. My other concern is that for some reason the mfg installed 2 flip down tube mount jacks, one on either side of the tongue instead of a single jack. Someone stole one of the jacks off one side and the PO didn't replace it, so he would use one side to hold the trailer up, which caused the vertical wall of the angle iron to bow out slightly under the mounting point on that side, so I'm concerned that damaged the integrity and needs some reinforcement at least. I didn't see it before I bought the trailer, unfortunately. I cut off the mounting tubes from the tongue and welded on a single 10k drop leg jack in the center of the tongue.

I'll get some pics to put up tomorrow when there's daylight of what I'm working with. My friend with the welding shop who is letting me use his gear makes trailers built very well with thick wall tube tongues so he suggests to box in the tongue at the least for strength, so I started looking at options and trying to figure out myself what material would be best, so I figured it wouldn't hurt to get further input from the knowledge base here.

[phoenix02]

I just ran outside to take some pics of what I'm working with. You can see in the one pic from the under side of the tongue rail what I mean about it being bent out slightly where the jack was mounted.

https://ibb.co/m4cd95P
https://ibb.co/dbh8fPv
https://ibb.co/4jQqJHg

[NotaVegetarian]

Maybe let folks know where your located someone could be close enough to provide more assistance

[scsmith42]

I reinforced a similar trailer about 30 years ago by adding a C Channel to the outside of the existing tongue. In my instance, the C Channel was located the width of an ammo box outboard of the angle iron, so that I could store chains, etc inside .50 cal ammo boxes in the space between the old and new tongues. A new Bulldog coupler was installed at the front of the C channels, and the old angle was boxed into it.

Other than having a lot of tongue weight, it strengthened up the tongue dramatically.

[farmersammm]

If it's withstood the test of time, I'd not get real worried about it, but it's not the way I'd build one.

Given your constraints, I might want to consider taking some angle iron, and scabbing it to the existing angle iron, to make the tongue a channel iron tongue. Channel is exceptionally strong in the orientation that the tongue is in. And.............it's an easy fix, considering how the trailer is built, and the fact that you don't want to demolish it to reinforce it. The additional angle would be easily welded to the existing angle. Simple coupla lap joints to marry it all together.

[Oldiron2]

I just ran outside to take some pics of what I'm working with. You can see in the one pic from the under side of the tongue rail what I mean about it being bent out slightly where the jack was mounted.

https://ibb.co/m4cd95P
https://ibb.co/dbh8fPv
https://ibb.co/4jQqJHg

If you can post the pictures directly on this site, we all can see them. Some of us can't (or won't) open links to elsewhere.

[farmersammm]

If you can post the pictures directly on this site, we all can see them. Some of us can't (or won't) open links to elsewhere.

Agreed. PITA to go to other sites to see pics.

[phoenix02]

Sorry, I was posting from my phone and didn't see how to insert photos on the forum so I found a place to upload them to here you go-

[phoenix02]

I had a different idea, to add some 3x3 tube, splayed out wider to reinforce the tongue, then a couple straps at the bottom of the now 4 tongue members to reinforce the main angle iron tongue at the two points the moat downforce will be seen, at the deck jinction and where the new 3x3 miters into the existing tongue.

Black is trailer deck, green is existing tongue, blue is new 3x3 tube and purple is straps under the tongue.

[Eelspike]

I see the deflection and agree it is a cause for some concern. The load on the tongue of a trailer is dynamic an switches between heavy weight on the tongue to an uplift load when the trailer bounces over the road. When the trailer is loaded normally or with a load in front of the axles the vertical leg of the angle is in tension, that look like a failure in tension so that leg pull to the outside as the angle buckled a little. It can be reinforced several different ways. I would lean toward pulling the deck up and straightening the angle and sistering the angle with a channel about 2-inch deeper than the angle. Where the channel is welded to the angle at the top the the joints should be beveled to get a nice deep weld like 4-inches in 12- inches, where the vertical leg of the angle is welded to the back of the channel the lap joint should be welded 4-inches in 12 again. Fit up can be drawn tight with a bridge clamp. Depending on welding skills and the availability of equipment you can flip the trailer so as to avoid the overhead welding. I would do the job with 1/8 7018 but would probably block it up high to do the overhead so as not to be crawling around on my back.

[Sberry]

Look it over for cracks. Repairs wont hurt but dont rebuild everything you see, wont ever get anything done. Second, the trailer isnt hooked to a concrete block or a semi truck which is solid, its hooked to rear suspension of a lighter truck which gives. Load it right.

[Oldiron2]

I need to reinforce a trailer tongue on a trailer. it is a 28ft flatbed and the tongue is 3x5x.25 angle iron. the perimeter of the main deck is 5x6.7 C Channel, I have no clue why the manufacturer made the tongue out of angle iron, but they did ...
...
Trailer is a double axle 28ft 12k. I will have a 2006 Suburban 2500 on the back over the axles and a thousand or two lbs of housewares, etc, in front of that, so it will be close to capacity but still under 12k gross. Towing with a 96 F350 dually with a round bar WD hitch.
Thanks!

International Harvester has information in its manuals about repairing and reinforcing truck frames, including those made of heat-treated steel. I might be able to scan or photograph some of it and post that here, if you're interested.

Based on your pictures and description, I'd consider doing what this quick sketch below shows, the reinforcing starting near the hitch and extending to near the axle, perhaps tapering the two legs in width towards the angle's corner at the back end. Where the cross piece (holding the jack) is, I'd have to see it to decide whether to have vertical welds from the reinforcing to it or if another added piece at the joint is useful.

BTW, I'm assuming you live somewhere like Arizona [Phoenix02] where moisture getting between the parts won't cause rust and corrosion unless preventative measures are taken.


Sorry about the lack of good penetration on my two welds, particularly the top right one. I know I'll hear about it from John T...
Attachment 1739888

[Leogl]

I wouldn’t try put a angle iron on top of another angle the corners aren’t going to fit right gonna involve a bunch of grinding I personally would put a piece of 1/2 inch flat bar on the outside plug weld and skip weld the vertical flat welded to the existing angle is gonna hold all your gonna get on the trailer I think if you put 1/2 x 6 on that 5 inch side of that angle

[Boostinjdm]

Try to straighten the bent area and run it. That flexing you are worried about is keeping the welds from cracking.

There are 2 ways to build a trailer. Flexy or super stiff. Anything in between will cause failures at connections.

[farmersammm]

I wouldn’t try put a angle iron on top of another angle the corners aren’t going to fit right gonna involve a bunch of grinding I personally would put a piece of 1/2 inch flat bar on the outside plug weld and skip weld the vertical flat welded to the existing angle is gonna hold all your gonna get on the trailer I think if you put 1/2 x 6 on that 5 inch side of that angle

You can avoid the inside corner curve if you space the angle. Temporary spacers, about maybe 3/8" wider than your finish height/width, will hold it proud of the curve while welding. It's the way I made the fixtures I use on the welding table. Two pieces of 2 1/2 angle will give you 3" channel if you space it this way. PITA, but doable.

That inside radius on angle presents a ton of problems like you mention.

[Oldiron2]

You can avoid the inside corner curve if you space the angle. Temporary spacers, about maybe 3/8" wider than your finish height/width, will hold it proud of the curve while welding. It's the way I made the fixtures I use on the welding table. Two pieces of 2 1/2 angle will give you 3" channel if you space it this way. PITA, but doable.

That inside radius on angle presents a ton of problems like you mention.

Rounding the corner of the reinforcing piece isn't that difficult using an angle grinder, IMHO.

[Eelspike]

That angle deflected under a load which means the tongue section is now bent upward starting at the leading edge of the trailer deck - that should be fixed because it has already failed. Straightening the angle and reinforcing it or even rebuilding the the tongue section is not complicated that is you can cut the angle out and replace it with a channel or even another angle provided you have the fabrication and welding skills. This Lincoln project book has a lot of details on DIY trailers and i'm sure there are many online trailer plans. If it's hard or time consuming to straighten out the deflection in the angle then replacing it may be cheaper.

[Oldiron2]

That angle deflected under a load which means the tongue section is now bent upward starting at the leading edge of the trailer deck - ...

I don't think the OP said that had happened, only that previously using only one jack had twisted or bent the frame member in that one spot. I'd expect that could be straightened by clamping it to a heavy tube, followed by judicious peening to set the grain, before reinforcing the whole length.

[phoenix02]

You are correct, oldiron2- the angle bowing out is only on the passenger side if the tongue, about a foot in front of the tonge to deck junction, where a swing down jack was welded to the frame and sat off-axis for too long, prying the vertical leg outward at that point. There is no other buckling or bending on the tongue.

[Eelspike]

The stress riser is the junction of the deck and tongue the leg of the angle looks as if it deflected under load. If you can level the trailer deck you can measure whether the tongue is bent up significantly. If the angle was distorted by the jack I would expect the vertical lag to be bent right at the jack only no under the deck as it appears in the picture. You can also get a square under there and measure for square on the between the vertical leg and the cross member on the trailer deck frame on both side. You might need to nip the corner of the square to do that be a weld there.

[Eelspike]

Maybe it is just the picture but the angle looks bowed out to me.

[phoenix02]

Here's some pics in the daylight. The angle is only bent out where the pipe mount was welded, not further back. What you were seing there was out of focus tabs welded to the tongue under the deck to support the deck. Other than that one spot where the jack bent it out, the tongue is in good shape. There is no bending or deformation at the deck junction. I have a crane mounted to the front corner that I use some RV screw jacks under it to support the corner when using the crane, but as you can see, with just the weight of that crane on there in the corner it causes a torsion flex.